Present invention embodiments relate to an airflow perturbation device and techniques for measuring parameters of respiratory mechanics, and more specifically, for measuring respiratory resistance of ventilated patients.
Patients suffering respiratory distress often breathe using a pulmonary ventilation device. A pulmonary ventilation device (or ventilator) breathes for the patient by providing an intermittent high pressure to drive air into the lungs during inhalation and then allowing air to escape from the lungs during exhalation. The patient and ventilator form a closed system not directly in contact with the atmosphere.
Knowledge of the respiratory resistance of the patient during ventilation may be useful because higher resistances require more pressure and time to deliver a given tidal volume of air to the lungs. If ventilator pressure is set too high, then respiratory damage can occur due to lung over inflation. Such damage may disable the patient for the remainder of her or his lifetime. However, conventional approaches to estimating the respiratory resistance of ventilated patients may lack accuracy and do not lend themselves to constant monitoring or distinguish between inspiratory resistance and expiratory resistance.